LAUSR

Abstract Fast-track computational prediction of efficient thermoelectric materials is crucial for designing future thermoelectric generators. In the present study, an attempt has been made to estimate the thermoelectric figure of merit ( Z T ) of hexagonal KBaBi, a topological insulator by employing first-principles calculations based on Density Functional Theory (DFT) and Boltzmann transport theory. KBaBi, a member of ternary honeycomb compounds has been chosen due to its high band valley degeneracy and hence high density of states effective mass which may lead to possible high-power factor ( S 2 σ ). Therefore, to estimate the ZT , properties such as mechanical, phononic, electronic, and transport phenomena of KBaBi have been evaluated. It is observed that KBaBi exhibits low average sound velocity ( v a ) and Debye temperature ( θ D ) resulting from soft acoustic phonon modes. The study reveals larger Seebeck coefficients than the minimum requirement of 200 ​μV/K along a-axis ( S a ) and c-axis ( S c ) for n and p-type KBaBi respectively, over a broad range of temperature and carrier concentration. Moreover, the calculated relaxation time ( τ ) based on deformation potential theory suggests the higher p-type conductivity ( σ ) along c-axis. It also unveils reasonably low lattice thermal conductivities ( k lat ) along a (2.09 Wm−1K−1) and c-axes (2.99 Wm−1K−1) at room temperature. Finally, we report a promising Z T of 1.04 for p-type KBaBi along c-axis despite having strong bipolar effect.